The present invention relates to a method of forming images on two surfaces of a sheet in accordance with a page order of documents and, more particularly, to a method for respectively forming images on the two surfaces of a sheet when an odd number of documents is prepared.
In general, two-side image formation is well known when images of a plurality of documents are formed on two surfaces of sheets. In a conventional image formation method of this type, a problem exists when images are formed on sheets in the order reverse to a page order and the number of documens is an odd number. In this case the upper surface of the first sheet is kept blank, so a continuous page order of the resultant images cannot be obtained, resulting in inconvenience. In the conventional image formation method, as shown in FIGS. 1 and 2, first, an odd number of stacked documents P1 to P7 are fed one by one, and even-numbered documents P6, P4 and P2 are sequentially processed by an image forming apparatus B. In this case, each document image is formed on one surface of each of the sheets Q sequentially fed. Second, the documents P1 to P7 are fed in the order named. Odd-numbered documents are sequentially processed, and each image is formed on the other surface of each of the sheets Q, thereby completing two-side image formation. An image P1' corresponding to the document P1 is formed on lower surface of the uppermost sheet. Referring to FIGS. 1 and 2, reference symbols P1', P2', P3', . . . and P7' denote images corresponding to the documents P1, P2, P3, . . . and P7, respectively.